Level 36
An adware campaign supported by as many as 182 mobile apps managed to push advertisements to millions of users on Google Play and third-party Android store.
Most of the apps made it to the official Android repository and just eight of them had been installed more than nine million times before they were finally removed.

The ad-spewing conduct was masked by the functionality related to games and phone camera; the sort of apps that are very popular among Android users. The software would function as expected by the user, for at least 30 minutes; then the malicious code would kick in blasting full-screen advertisements that could not be closed immediately.